Wearable weight distribution devices for reducing injury risk: How varying amounts of body armor offloading affect biomechanics and comfort

Abstract

Soldiers experience high rates of back injuries from wearing heavy body armor. Wearable weight distribution devices that offload body armor weight to the hips might help mitigate injury risk. However, it is unclear how much offloading is practical without negatively impacting comfort or biomechanics. We explored this knowledge gap by testing 13 veterans while wearing a 15.6 kg body armor vest and a novel weight distribution device. For each trial, the device was adjusted to offload a percentage of the body armor weight. We tested four conditions: ZERO (0%), LOW (∼30%), MED (∼60%), and HIGH (∼90%). We found that LOW, MED, and HIGH offloading of the shoulders and back did not negatively affect trunk muscle activity or posture. Overall user comfort also improved. All participants preferred a portion of the body armor weight distributed to their hip belt, highlighting the potential for these devices to relieve people in occupations that wear body armor.